This invention relates to imaging material properties in natural-fiber-containing materials. Rapid and accurate characterization of material properties, which can include, but are not limited to, moisture content, fiber structure, and grain structure (e.g., knots or imperfections), can be critical in determining the quality of a material and/or the ability of the material to be processed into various products. Many of the current systems for measuring material properties must contact the natural-fiber-containing materials and/or do not provide images. For example, many traditional systems for measuring moisture content use a “feeler” device that contacts the material to determine electrical conductivity. The feelers can accumulate dirt and wear out. Other systems, including those involving electromagnetics, typically perform spot measurements of moisture content and do not create images of the material showing localized moisture. Still other systems generate maps, but not true images, of fiber structure, grain structure, and/or knot distribution. Accordingly, a need exists for tools to image material properties in natural-fiber-containing materials without contacting the materials.